KR101405400B1 - Dielectric barrier dischagre lamp with a retaining disc - Google Patents

Abstract

The dielectric barrier discharge lamp (1) has a discharge vessel including an outer tube (2), and an outer electrode (6) is arranged outside the outer tube. The elongated internal electrodes 7, which at least indirectly enter the discharge vessel by the at least one holding disk 8, are arranged axially in the external tube 2. [ To this end, the holding disc extends substantially from the inner electrode 7 to the inside of the outer tube 2. The holding disk 8 is loosely supported on both sides in the longitudinal direction by the left supporting means 9a-9c and the right supporting means 10a-10c.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a dielectric barrier discharge lamp,

The present invention is based on a dielectric barrier discharge lamp having a tubular discharge vessel enclosing a discharge medium.

A discharge lamp of this type typically comprises a first elongate electrode arranged in a tubular discharge vessel and hereinafter also referred to as an internal electrode and a second elongated electrode generally arranged outside the tubular discharge vessel, It has a long electrode.

If the inner electrode is in direct contact with the discharge medium, the outer electrode is impeded by the wall of the discharge vessel as a whole, so that there is a discharge that is imbibed as a whole on one side. If the internal electrodes are likewise separated from the discharge medium by a dielectric, there is a discharge that is imbibed oil-globally on the two sides. This can be done, for example, by the fact that the internal electrodes are arranged in the inner tube. The inner tube is coaxially arranged in the tubular discharge vessel. In other words, the discharge vessel in this so-called coaxial double-tube arrangement has an inner tube coaxially arranged in the outer tube, the two tubes being arranged such that both ends of the tubes are connected to each other and thus form a gas-tight discharge vessel do. The discharge space surrounded by the discharge vessel therefore extends between the inner tube and the outer tube in this case.

In any case, the constant arcing distance between the outer electrode and the inner electrode along the tubular dielectric barrier discharge lamp is dependent on the ramp longitudinal axis and the effective ramp to achieve a uniform discharge and hence uniform radial density as viewed along the lamp circumference. It needs to be guaranteed for operation. Therefore, the inner electrode and / or inner tube need to be arranged as centrally as possible in the outer tube. Particularly for long lamps, there is a further problem of sagging against the inner electrode or inner tube because the inner tube naturally has a smaller diameter than the outer tube. In extreme cases, this can lead to damage to the lamp, for example during transport.

This type of lamp can be used in particular for UV radiation of processing techniques such as surface cleaning and activation, photolitics, ozone generation, beverage purification, metal-plating and UV curing. In this situation, the term radiator or UV radiator is also conventional.

Document EP 1 147 535 B1 discloses a discharge lamp with a dielectric barrier on one side. In this case, a first coiled inner electrode 6 is wound on the inner tube 9 (see FIG. 1 of the above document). The inner tube 9 is coaxially arranged in the outer tube 3, and strip-shaped outer electrodes 7 are arranged on the outer side of the outer tube in parallel with each other and apart from each other. In order to support the inner tube 9, this document proposes a retaining disk 15 which is pushed against the inner electrode 6, for example. There is no disclosure relating to fixing of the holding disk 15, which is required to be fixed inside the outer tube 3.

It is an object of the present invention to provide a tubular dielectric barrier discharge lamp having an improved maintenance arrangement for an inner electrode or an inner tube surrounding the inner electrode.

The object is achieved by a discharge lamp comprising a discharge vessel having an outer tube surrounding a discharge space filled with a discharge medium, an outer electrode arranged outside the outer tube, an elongated inner electrode axially arranged in the outer tube, At least one holding disc having an axial bore extending therefrom, the holding disc extending substantially from the inner electrode to the inner side of the outer tube so that the inner electrode is at least indirectly centered in the discharge vessel And the retaining disc is loosely supported on its both sides in the direction of the longitudinal axis by the left support means and the right support means.

Particularly advantageous configurations can be gathered from the dependent claims.

The basic concept of the present invention is that the support disk is not fixedly connected to the discharge vessel to arrange the inner electrode or the inner tube in the center, but simply the support disk is loosely supported on both sides so that the sustain disk slides along the ramp longitudinal axis Is reliably prevented.

That is, the present inventors have found that the solid connection between the sustaining disc and the discharge vessel has some disadvantages. For example, the stresses and / or cracks of the holding disc that occur as early as possible during the manufacture of the holding disc by the solarization or during the lamp operation extend onto the discharge vessel, It was found that it could cause destruction. In addition, the discharge vessel is deformed when it is directly welded to the holding disk. Due to the excellent transparency required for electromagnetic radiation in the ultraviolet range, the material of the discharge vessel, typically made of quartz glass, is weakened at its joints. For example, when mechanical loading occurs as a result of vibrations during operation of the impact or discharge lamp during transport, such localized weakening of the quartz glass may act as an undesired breakdown point and ultimately cause breakage of the discharge vessel. Attempts to spot-weld the retention disc on the outer tube, or if provided, on the inner tube of the discharge vessel did not produce any satisfactory results. Although the spot welding makes it possible to keep the damage to the discharge vessel within acceptable limits, the welded joints are separated during loading, and as a result permanent fixation of the retaining disk by spot welding is not guaranteed.

According to the invention, two support means are provided for the retaining disc, which only loosely supports the retaining disc on both sides of the retaining disc to prevent the retaining disc from sliding in the axial direction.

In the simplest case, one support means comprises, for example, a material bead applied to the inner tube, or only to the inner tube piece if applicable, for example. In this case, the holding disc is arranged only between the two material beads. It may also be advantageous to provide more than one material bit per side, in particular to distribute the material beads uniformly over the circumference. It is important that each distance A between the material bead on the left and the corresponding material bead on the right is greater than the thickness D of the holding disk so that the holding disk loosely mounts. At least it is at least necessary that the margin A-D is larger than the thermal expansion of the materials so that the loose holding disc is initially secured by heating during manufacturing or during lamp operation so that undesired stresses do not occur. In such an environment it has proven advantageous if the relationship between the distance A between the two support means and the thickness D of the retention disc is as follows:

(1)

(One)

Where 0.1 < x < 1000, especially 1 < x < 250. This can first cause the retaining disc to loosely hold against the support means and thus prevent any stresses from being transmitted from the retaining disc. Secondly, in terms of manufacturing technology, it is also possible to arrange the material beads correspondingly. Considering typical manufacturing tolerances, for example, margins (A-D), which are typically about 1 mm, have proven feasible. The thickness (D) of the holding disc must first be as small as possible so as not to destroy the electrical and optical properties of the lamp as little as possible. Second, the retaining disk needs to be mechanically stable enough. Experience has shown that a thickness (D) of about 1 to several millimeters, for example 2 mm, is sufficient for a corresponding holding disc made of quartz glass.

Essentially, the support means according to the present invention can be secured to the inside of the outer tube and to the outside of the inner tube if provided. However, the outer side of the inner tube is preferred because it is simpler in terms of manufacturing techniques to apply the support means to the outer side of the inner tube, since the inner side of the outer tube is particularly less accessible than the central region of the tube to be. In this case, the first material bead is applied to the outside of the inner tube, or a plurality of material beads are distributed in a circular shape on the circumference of the inner tube. Then, the retaining disc is fitted and finally one or more material beads are again applied to the outside of the inner tube behind the disc, exactly at the appropriate distance from the material beads on the other side. This only prevents the retaining disc from sliding and ensures that the retaining disc is supported by the material beads so that no stresses are actually conveyed accordingly.

Preferably, when the holding disc is fitted, the supporting ring is also fitted, and then only the finishing material bead (s) is applied. The support ring allows the retaining disk to have a greater distance from the point where heat is induced when the material bead (s) are applied, for example when the quartz bead is welded to the quartz tube, thereby being less affected by the thermal load . For this reason, no support ring is required on the other side of the retaining disc, as long as the material bead (s) are welded and the retaining disc is fitted. In time-saving manufacturing variants, the material beads on both sides of the holding disc are welded simultaneously. In this case, one support ring is preferably provided on each side of the holding disk.

In general, the support ring is loosely mounted on the inner tube so that the retaining disc can be prevented from sliding far in the direction of the longitudinal axis simply by the at least one material bead, or the relatively loose support ring can be prevented from sliding in at least one material It is possible to hit the bead and mechanically damage the material bead. The support ring may alternatively also be welded directly to the inner tube so that this possible problem at the beginning is eliminated. To this extent, the term material bead should also be understood in general aspects to include welded joint properties of spot welds. Thus, in the case of spot welding, the support ring is fixedly connected to the tube through at least one material bead.

A further advantage of the support ring is that it uniformly distributes the force on the fixed or fixed part in any case when the retaining disc is moving. That is, by the support ring, the mechanical loading on the discrete material bead (s) is reduced.

The support ring may also have a slot or may comprise two or more segments. If appropriate, each segment of the support ring is individually spot-welded, i. E. Connected to the material bead applied to the tube.

In order to keep the flow resistance as low as possible during vacuum and subsequent charging of the discharge space of the dielectric barrier discharge lamp, the retaining disk preferably has one or more openings, for example bores or cutouts .

The retaining ring and the support ring are made of an electrically insulating material, preferably an insulating material which is highly resistant to ultraviolet radiation, for example quartz glass, ceramic or the like.

The support ring preferably has a thickness S in the range between approximately 0.5 mm and 3 mm. The width (B) of the support ring is preferably in the range between approximately 2 mm and 6 mm.

The invention will be described in more detail below with reference to exemplary embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A shows a longitudinal cross-sectional view of a dielectric barrier discharge lamp according to the present invention. FIG.
Figure 1B shows a cross-sectional view of the lamp shown in Figure 1A.
Fig. 2A shows an enlarged view of the deformation of the lamp shown in Fig. 1A.
Figure 2b shows a longitudinal cross-sectional view of the support ring of Figure 2a.
Fig. 3 shows an enlarged view of a further modification of the lamp shown in Fig.

The same or functionally equivalent elements are provided with the same reference numerals in the figures.

1A and 1B show a very simplified view of a longitudinal section and each show a cross-sectional view of a first exemplary embodiment of a dielectric barrier discharge lamp 1 according to the invention. The elongate discharge vessel of the lamp 1 comprises an outer tube 2 and an inner tube 3 in a coaxial double-tube arrangement, so that the inner tube and the outer tube define a longitudinal axis of the discharge vessel. The typical length L of the tubes is between about 10 and 250 cm, depending on the application. The outer tube 2 has a diameter of 44 mm and a wall thickness of 2 mm. The inner tube 3 has a diameter of 20 mm and a wall thickness of 1 mm. Therefore, the radius range of the discharge between the inner electrode and the outer electrode is approximately 10 mm ([44 mm - 2 × 2 mm - 20 mm] / 2). The two tubes 2,3 are made of quartz glass which is transparent to UV radiation. In addition, the discharge vessel is sealed at both end sides so as to form an elongated discharge space 4 in the form of an annular gap. For this purpose, the discharge vessel has in each case annular container sections 5 suitably formed at its two ends. In addition, an exhaust tube (not shown) is attached to one of the vessel sections 5 and is first used to evacuate the discharge space 4 and then fill the discharge space 4 with 15 kPa of xenon. A wire mesh 6 is drawn out of the wall of the outer tube 2 to form the outer electrode of the lamp 1. [ The metal flexible structural tube 7 made of stainless steel is arranged inside the inner tube 3 and functions as an inner electrode. The holding disc 8 made of quartz glass with a thickness D of 2 mm is loosely arranged at approximately the center of the discharge vessel. The retaining disc 8 has a central bore so that it can be easily placed on the inner tube 3. In addition, the holding disk 8 has four bores 81-84 for maintaining the flow resistance as small as possible while the discharge space 4 is kept in a vacuum and continuously charged. Three quartz glass beads 9a-9c, 10a-10c are attached to the surface of the inner tube 3 on the left and right sides of the holding disk 8, respectively. The quartz glass beads are uniformly distributed in the form of a circle on the circumference of the inner tube on each side, i. E. Arranged at an angular distance of 120 [deg.] (See Fig. The distance A between the three quartz glass beads 9a-9c on one side and the quartz glass beads 10a-10c on the other side is approximately 3 mm, so that a margin of approximately AD = And is still maintained with respect to the holding disc 8 arranged between the glass beads. Corresponding to the relation (1), a value of 2 for the parameter x (x = D / [A-D]) is derived from this equation. The diameter of the retaining disc 8 is approximately 1 mm smaller than the inner diameter of the outer tube 2 so that there is still a slight margin and the outer tube 10 can be inserted into the inner tube 3).

Figure 2a shows a partial view of one variant. The figure shows only the central region of the lamp 1 'with the holding disc 8 and the supporting means on both sides. In the first exemplary embodiment, three quartz glass beads 11a-11c are applied to the inner tube 3 on the right side of the holding disc 8. The support means additionally comprises a support ring 12 which is placed on the inner tube 3 and which is provided with two quartz glass beads 13a and 13b on the left side of the retaining disc 8, Was fixed to the tube (3). The support ring 12 has a thickness S of approximately 2 mm and a width B of approximately 5 mm (see Fig. 2b in this connection). The support ring 12 is arranged such that when the edge of the support ring 12 farther from the retaining disc 8 is bonded to the two quartz glass beads 13a and 13b, (B) of the retaining disc (8). This helps the support ring 12 to reduce thermal loading or helps the thinner holding disc 8. The distance A between the three quartz glass beads 11a-11c on the right side and the left support ring 12 is approximately 3 mm, resulting in a margin of approximately AD = 1 mm, Gt; 8 &lt; / RTI &gt;

The variation of the lamp 1 "shown in Figure 3 differs from the previous variant only in that the support means comprise support rings 12 and 14 respectively on both sides of the retaining disc 8. In this case, The support ring 14 of the first support ring 12 is fixed to the inner tube 3 with two quartz glass beads 15a and 15b in the same manner as the support ring 12 on the left is made in the previous modification. 12 and 14 is approximately 3 mm, so that a margin of approximately 1 mm is maintained for the holding disc 8 even in this variant.

Claims (16)

As the dielectric barrier discharge lamp (1)
A discharge vessel having an outer tube (2) surrounding a discharge space (4) filled with a discharge medium,
An outer electrode 6 arranged on the outer side of the outer tube 2,
An elongated inner electrode 7 arranged axially in the outer tube 2, and
At least one retaining disk 8 having an axial bore through which the elongate internal electrode 7 penetrates, the retaining disk 8 extending from the internal electrode 7 to the external tube 2 , So that the internal electrode 7 is centered in the discharge vessel-
Lt; / RTI &gt;
The holding disk 8 is loosely supported in the axial direction on both sides by the left support means 9a-9c and the right support means 10a-10c, and the two support means 9a- 10c have a distance A from each other and the distance A is greater than the thickness D of the holding disc 8,
Dielectric barrier discharge lamp. The method according to claim 1,
The inner electrode 7 is surrounded at least in the region of the holding disk 8 by an inner tube 3 on which the holding disk 8 is held,
Dielectric barrier discharge lamp. 3. The method of claim 2,
The inner tube (3) extends along the entire length of the lamp in the discharge vessel and the inner tube (3) and the outer tube (2) are arranged in a coaxial double-tube arrangement in gas- Connected,
Dielectric barrier discharge lamp. The method according to claim 2 or 3,
The two support means (9a-9c; 10a-10c) are fixed to the outside of the inner tube (3)
Dielectric barrier discharge lamp. The method according to claim 1,
The two support means being fixed to the inside of the outer tube,
Dielectric barrier discharge lamp. delete The method according to claim 1,
The relationship between the distance A between the two support means 9a-9c (10a-10c) and the thickness D of the holding disk

, Where 0.1 < x < 1000,
Dielectric barrier discharge lamp. The method according to any one of claims 1 to 3 and 5,
Characterized in that the two support means each comprise at least one material bead (9a-9c; 10a-10c), the material beads being connected to the inner tube (3)
Dielectric barrier discharge lamp. 9. The method of claim 8,
Characterized in that at least one support means on the one side of the retaining disc 8 comprises a support ring 12 which supports the retaining disc 8 and the corresponding at least one material bead 13a, 15b,
Dielectric barrier discharge lamp. 10. The method of claim 9,
The support ring having a slot,
Dielectric barrier discharge lamp. 10. The method of claim 9,
Wherein the support ring has two or more segments, each segment being connected to a material bead,
Dielectric barrier discharge lamp. 10. The method of claim 9,
The support ring having a thickness (S) in the range of 0.5 mm to 3 mm,
Dielectric barrier discharge lamp. 10. The method of claim 9,
Wherein the width (B) of the support ring is in the range of 2 mm to 6 mm,
Dielectric barrier discharge lamp. The method according to any one of claims 1 to 3 and 5,
Wherein the retaining disc has one or more openings in addition to the axial bore.
Dielectric barrier discharge lamp. 8. The method of claim 7,
1 < x < 250,
Dielectric barrier discharge lamp. 15. The method of claim 14,
Said one or more openings being additional bores 81-84,
Dielectric barrier discharge lamp.

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